Hot melt ink compositions are known in the art.
A hot melt ink composition is an ink composition that is solid at room temperature and liquid at elevated temperature. Inks of this kind are also known as meltable inks or phase change inks. Known hot melt ink compositions comprise for example a crystalline material, a colorant and a binder.
In a printing device, for example an ink jet printer, the ink is melted and transferred to substantially closed ink ducts which lead at one end into an orifice. As a result of a sudden pressure rise in the duct, produced for example by rapidly reducing the volume of the ink duct or rapidly evaporating some of the ink in the duct, a drop of ink may be ejected from the duct through the orifice. In this way an image may be built up from individual ink drops on a receiving medium. Hot melt inks contain a carrier material with a melting point higher than room temperature. The ink may melt in the printing device. Hot melt inks of this kind have the advantage that they set rapidly on the receiving medium, so that the print quality is less dependent on the type of receiving medium. Print quality is an important aspect for evaluating the quality of a hot melt ink composition.
EP 1 221 467 B1 describes a hot melt ink composition, the hot melt inkjet ink composition being solid at room temperature and liquid at an elevated temperature, comprising a binder, a colorant and a crystalline material, wherein the crystalline material is a compound according to
where R1 and R′1 are the same or different and are selected from a C1-8 alkyl or a C1-8 alkoxy group, R2 is a C1-12 linear alkane diyl or a C5-12 alkane diyl containing a cyclic group, and n and m are the same or different and are equal to 1, 2 or 3. However, regarding print quality, there is room for improvement.
It is therefore an object of the invention to provide a hot melt inkjet ink composition providing printed images with an improved print quality. It is a further object of the invention to provide a method for preparing a hot melt inkjet ink composition that provides printed images with an improved print quality.